Preparation, crystal structure, and thermal decomposition of the energetic compound [Co(IMI)₄(PA)](PA) (IMI = imidazole and PA = picrate)

The novel multi-ligand coordination compound [Co(IMI)₄(PA)](PA) (1) was synthesized by using imidazole (IMI) and picrate (PA) and characterized by elemental analysis and FT-IR spectroscopy. The crystal structure was determined by X-ray single crystal diffraction and the crystallographic data showed that the compound crystallizes in the triclinic space group P1 (α = 8.839(2) Å, b = 13.550(3) Å, c = 13.840(3) Å, α = 68.386(6)°, β = 88.349(9)°, and γ = 87.494(9)°). Furthermore, the Co^II ion is six-coordinated by four nitrogen atoms from four imidazole ligands and two oxygen atoms from a PA group. Its thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetry-derivative thermogravimetry (TG-DTG) analysis. The kinetic parameters of the first exothermic process were studied by using Kissinger's and Ozawa's method, respectively. The energy of combustion and the enthalpy of formation were measured and calculated. They showed good combustion performance of the compound. Additionally, the sensitivity properties were determined with standard methods. The results of all these studies showed that [Co(IMI)₄(PA)](PA) has potential application as ignition composition.